1. Field of the Invention
The subject invention is directed to catheters, and more particularly, to a urinary drainage catheter having a lubricated sheath associated therewith to reduce irritation to the urethra during insertion and removal of the catheter, and while the catheter is positioned therein in a functioning mode.
2. Description of the Related Art
Urethral catheters that are placed within a patient's lower urinary tract are well known in the art. One type of urethral catheter is a retention catheter. Retention catheters are supported in the patient's bladder to continuously remove urine therefrom. One type of urinary retention catheter is known in the art as a Foley catheter. It consists of an elongated tube through which extends a main drain lumen. The catheter is placed through the patient's urethra so that the distal end thereof extends into the patient's bladder and the proximal end remains outside the patient's body. An inlet opening is provided at the distal end of the catheter to allow urine to drain into the main lumen and pass into a collection bag associated with the proximal end of the catheter.
Foley catheters are retained within the patient's bladder and urethra by an inflatable balloon located at the distal end of the elongated tube proximate to the inlet opening of the main lumen. An inflation lumen connects the balloon to the proximal end of the catheter so that a liquid may be passed under pressure to the balloon to expand the balloon. A valve is generally provided to maintain the liquid under pressure so that the balloon remains inflated.
Often, a urinary catheter will remain within the urethra for years at a time, presenting general discomfort to the patient. Such discomfort will be heightened when there is relative movement between the catheter and the urethra. This discomfort results from friction between the outer wall of the catheter and the inner wall of the urethra, and is magnified by even minimal movement of the patient. In addition, the internal cardiac rhythm of the body on breathing, turning in bed and walking may create an irritating friction generating movement of the urethra relative to the catheter. This irritation may be compounded by infection, further complicating and lengthening patient recovery. Even greater discomfort will be experienced when the catheter is removed from the urethra after use.
Several prior art devices have been provided to reduce such discomfort through the use of lubricants, as described, for example, in U.S. Pat. Nos. 3,726,281 and 5,098,379. In U.S. Pat. No. 5,209,726, a catheter is disclosed which has an elongated body enclosed by a resilient sleeve which defines a cavity containing a lubricating substance effective to permit the sleeve to slide along the outer surface of the catheter body. Thus, in use, when the catheter body moves in response to movements of the patient's body, the sleeve will move relative to the urethra. However, during insertion and removal of this catheter, significant frictional contact will occur between the sleeve and the urethra, causing considerable discomfort to the patient. The subject invention provides an improvement over these prior art devices.